Media Center
Climate Bulletin for Sri Lanka (Week of 15 December – 22 December 2023)
Highlights
Rainfall Prediction: High probability of heavy rainfall (> 100 mm) is predicted for Sabaragamuwa, Northern provinces and fairly heavy rainfall is predicted for Central, Uva, North Western provinces during 15 – 21 Dec.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 10.4 mm and hydro catchment was 16.5 mm. Extreme rainfall (> 150 mm/day) was in Badulla. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 4 – 10 Dec , up to 4 m/s of south westerly winds were at 850 mb (1.5 km). During 14 – 20 Dec, up to 8 m/s of easterly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.25 – 1.5ºC above normal. From 7 – 13 Dec, maximum daily temperature was recorded in Moneragala (34.3ºC) and Ratnapura (33.8ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following area: Badulla.
Daily Average Rainfall in the Met stations for previous week of (6th December – 13th December) = 10.4 mm
Maximum Daily Rainfall: 94.9 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: South westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (15th December – 21st December), heavy rainfall is predicted for the Sabaragamuwa, Northern provinces and fairly heavy rainfall is predicted for the Central, Uva, North Western provinces and less rainfall is predicted for rest of the country.
Temperatures: The temperature will remain seasonably near normal for the country during 14th December – 20th December.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall moderately suppress the rainfall during 13th – 22nd December and slightly suppress the rainfall during 23rd – 27th December for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the December-January-February, 2024 season shows near normal precipitation.
Terminology for Rainfall Ranges
| Rainfall (During 24 hours of the period) | |
| Light Showers | Less than 12.5 mm |
| Light to Moderate | Between 12.5 mm and 25 mm |
| Moderate | Between 25 mm and 50 mm |
| Fairly Heavy | Between 50 mm and 100 mm |
| Heavy | Between 100 mm and 150 mm |
| Very Heavy | More than 150 mm |
